In the cities not covered, lack of real-time monitoring means inhabitants cannot check current pollution levels to protect themselves, and the government is unable to issue public warnings.

Around 88 million Indians – only 7% of the population – live in the 33 cities that have online air pollution monitoring that is available in real time, meaning that less than 10% of India’s 380 urban agglomerations are covered.

The two cities covered are the capital Delhi and Faridabad, an industrial hotspot in Northern India.

During a toxic episode in November in Delhi, the government was able to use the real-time system to warn citizens of an “emergency situation”, closing schools and temporarily halting production at construction sites and a coal power plant.

Although the government runs several monitoring networks that cover more than 200 cities and towns, measurements in most are only taken twice a week and are not available in real-time. Instead, a manual monitoring system means samples must first be sent to a laboratory to be assessed.

All of the cities in the top 10 are experiencing levels of the particulate PM10 three and half times the annual legal limit – and 10 times above international guidelines – according to data compiled by Greenpeace India for a report on the state of the nation’s air – published last week.

Where government data was unavailable for download, freedom of information laws were used to obtain government monitoring results.

Although media attention focuses on Delhi, some of the worst pollution hotspots – four out of the 10 most polluted cities – are found in the coal mining state of Jharkhand. It has a population of 32 million but not a single official real-time air pollution monitor.

Yet Jharkhand is the state googling for information about air pollution the most, well ahead of Delhi, per relative search interest metrics on Google Trends.

Across the country, search interest on air pollution has been rising steadily and reached the highest point on record – at least since 2004 – following the enormous pollution levels last October-November.

Not a single city in northern India met international safety guidelines for particle pollution in 2015. Less than 10% of the cities met India’s national air quality standards – which are three times as high as the WHO safety guideline.

Action

India’s pollution levels have been rising at an alarming rate as coal consumption almost doubled and oil consumption increased 60% from 2005 to 2015.

A Greenpeace India report last year showed that emissions from coal-based power plants were the largest source of increase in SO2 and NOx emissions in the country – two key pollutants contributing to India’s particle pollution levels.

Organizations such as TERI and CSE, along with Greenpeace, have started calling for a national action plan on air pollution to expand measures to reduce emissions from key polluting sectors – power plants, industry, agriculture and transport – beyond individual cities.